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Posted to commits@mahout.apache.org by sr...@apache.org on 2009/11/05 21:50:17 UTC
svn commit: r833159 - in
/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste:
impl/recommender/slopeone/MemoryDiffStorage.java model/DataModel.java
Author: srowen
Date: Thu Nov 5 20:50:17 2009
New Revision: 833159
URL: http://svn.apache.org/viewvc?rev=833159&view=rev
Log:
MAHOUT-195: improve docs about assuming DataModel.getPreferencesFromUser() returns prefs in order, and, use that a little better in MemoryDiffStorage
Modified:
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/MemoryDiffStorage.java
lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/model/DataModel.java
Modified: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/MemoryDiffStorage.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/MemoryDiffStorage.java?rev=833159&r1=833158&r2=833159&view=diff
==============================================================================
--- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/MemoryDiffStorage.java (original)
+++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/impl/recommender/slopeone/MemoryDiffStorage.java Thu Nov 5 20:50:17 2009
@@ -117,19 +117,20 @@
@Override
public RunningAverage getDiff(long itemID1, long itemID2) {
+
+ boolean inverted = false;
+ if (itemID1 > itemID2) {
+ inverted = true;
+ long temp = itemID1;
+ itemID1 = itemID2;
+ itemID2 = temp;
+ }
+
FastByIDMap<RunningAverage> level2Map = averageDiffs.get(itemID1);
RunningAverage average = null;
if (level2Map != null) {
average = level2Map.get(itemID2);
}
- boolean inverted = false;
- if (average == null) {
- level2Map = averageDiffs.get(itemID2);
- if (level2Map != null) {
- average = level2Map.get(itemID1);
- inverted = true;
- }
- }
if (inverted) {
if (average == null) {
return null;
Modified: lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/model/DataModel.java
URL: http://svn.apache.org/viewvc/lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/model/DataModel.java?rev=833159&r1=833158&r2=833159&view=diff
==============================================================================
--- lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/model/DataModel.java (original)
+++ lucene/mahout/trunk/core/src/main/java/org/apache/mahout/cf/taste/model/DataModel.java Thu Nov 5 20:50:17 2009
@@ -40,7 +40,7 @@
/**
* @param userID ID of user to get prefs for
- * @return user's preferences
+ * @return user's preferences, ordered by item ID
* @throws NoSuchUserException if the user does not exist
* @throws TasteException if an error occurs while accessing the data
*/